Test strips (e.g., biosensors) containing reagents are often used in assays for determining the concentration of an analyte in a fluid sample. Testing and self-testing for the concentration of glucose in blood is a common use for test strips. One method of obtaining a blood sample and analyzing the sample for determining the glucose level is with a lancing device and a separate blood collection device. In obtaining a blood sample, a drop of blood is obtained from the fingertip using the lancing device, and the blood is harvested using a test strip, which is then analyzed by a test unit that determines the concentration of glucose in the blood. Test strips are also used for determining the concentration or presence of various other analytes (e.g., fructosamine, hemoglobin, cholesterol, glucose, alcohol, drugs including illegal drugs, etc.) in a variety of body fluids (e.g., blood, interstitial fluid, saliva, urine, etc.).
A drawback associated with the use of physically separate lancing and collection devices is that a patient/user must manipulate two different instruments requiring the user/patient to bring the collection device (e.g., the test strip) to the area of skin that has been lanced to collect the sample. Because the user must align the collection device with the sample to be collected, a larger than necessary amount of sample often is produced and collected to ensure an accurate analysis. In other situations, not enough sample is collected for accurate analysis because the collection device is not properly positioned. This problem can be further compounded if the user has impaired vision or poor dexterity. Because test systems are requiring smaller volumes of blood for analysis, it is difficult to position a collection instrument for proper collection.
The surface condition of the skin affects the formation of a blood droplet at the lancet site on skin. Many individuals use hand lotions, have oily or sweaty skin, or do not dry their hands completely after washing which also affects droplet formation. Often users do not always cleanse the area of skin to be lanced with alcohol. These variations increase the wettability of the skin's surface causing the droplet to spread in an uncontrolled and unpredictable manner making it difficult to harvest the sample.
Further, the collection of blood samples on alternative sites such as the forearm is complicated by the presence of body hair because the sample (e.g., blood) has a tendency to “wick up” the hairs found on these parts of the body. Cleaning the lance site with alcohol does not alleviate this wicking problem. Thus, there exists a need for a lancing and collection device that co-locates the lancet and the collection point to accurately collect a blood sample for analysis.